Chromatography Forum

The FID detector on my 5890 II appears to be faulty. At room temperature the detector reads at about 400oC and will not return to the correct temperature. Of course I have tried sending methods and switching the GC off and on again, but the problem persists. I suspect that there is an issue with thermostat in the detector and wonder if anybody has experienced this problem before. Is it an easily fixable problem, or if I will have to buy a whole new detector.

Regards,

Jay

I could be several things at which could be replacing the thermal-couple or the board. Have you gotten a external thermal-couple near the jet to see is the detector is indeed the temperature at which it reads?

No I haven't tried using an external thermal-couple. I assume it's faulty as I had switched the GC off from the mains for a couple of hours to let the detector cool down (if it was really that temperature). When I turned it on again it still read ca. 400oC, but it was cool to touch. Even when there is no hydrogen or air supply it reads that high.

http://www.chem.agilent.com/Library/Sup ... a03152.pdf
Check the thermocouple is connected properly to the electronics and to the FID body. If it is its't probably kaput but it looks liek it's replaceable (item 21 onwards). If it's reading 400C when switched on you can bet it isn't really this hot.

buller,

Your RTD is probably shorting on your detector base. A very common problem on the 5890's once the insulation has worn off. You can get new RTD's from Restek. Replacing them is pretty straight forward on the detector side, replacing them on the electronics side you need to be careful that you get them into the electrical connector well and that they stay put when you re-connect the connector.

Best regards,

AICMM